Buoyancy system

ABSTRACT

The present invention provides a buoyancy system for moving an object in a body of water. The system includes at least one inflatable body which, when inflated, increases the buoyancy of the object, and an inflation apparatus to inflate the at least one inflatable body. The system also includes an activation system to activate the inflation apparatus. Upon activation of the activation system the inflation apparatus causes a gas to flow to the at least one inflatable body, causing the object to move.

FIELD OF THE INVENTION

The present invention generally relates to a buoyancy system for raisingor lowering objects within a body of water.

In one application of the invention the buoyancy system is designed toraise malfunctioning or damaged objects, such as submarines andaircraft, from a depth, and/or to maintain them at the surface.

In another application of the invention the buoyancy system is designedto raise and/or lower objects from deep water enabling them to be raisedand recovered at the surface of the water, or lowered into position. Theobject includes submerged ocean floor infrastructure such as sub-seatrees, manifolds and platform anchors.

BACKGROUND ART

There are inherent difficulties associated with operations conducted indeep water. These problems are typically associated with the increasingpressure encountered at increased depths, as well as the weight ofinfrastructure, such as cables, which increase the deeper the operationsare conducted.

At increased depths, the recovery of an object is increasinglydifficult. This has been highlighted by several marine accidents inwhich rescue equipment was not available for situations in which adamaged submarine or aircraft was submerged in water beyond a certaindepth. As a result, these accidents have resulted in fatalities.

Submarine escape and rescue/abandonment safety technology has evolvedover the last few decades. The first generation consisted of a means ofescape, which saw submarines being fitted with escape tower/hatches, andspecially designed escape suits that would provide an escapingSubmariner with both buoyancy and breathing air to reach the surface.This technique was, and indeed still is, limited by the depth at whichthe vessel lies. The second generation consisted of rescue using asubmersible or rescue bell. This significantly increased the depth atwhich personnel can be extracted from a submarine and is also much saferthan using escape suits.

However, both of these methods have significant limitations. If thesubmarine malfunctions or is damaged when operating in water deeper thanits collapse/crush depth, then the current escape or rescue methodscannot be employed to save the occupants. Moreover, it takes many daysto affect a rescue. During this time an increase in the internalpressure of the submarine, the consumption of vital survival stores(oxygen candles, carbon dioxide absorption devices, etc) and thedeterioration and contamination of the atmosphere sustaining life(hydrogen sulphide, chlorine gas, etc) could be fatal.

Another industry in which operations are increasingly occurring atgreater depths is the oil and gas industry. In this industry equipmentis frequently employed on the ocean floor for a number of varied reasonsand functions. The offshore oil and gas industry use equipment on thesea floor to extract fossil fuels and supply them to surface platformsand oil rigs. As the reservoirs of oil and natural gas at relativelyshallow depths are consumed exploration for more reserves has moved intodeeper water.

Positioning and recovering heavy equipment from the ocean floor is anexpensive process that requires significant assets. Currently, equipmentused on the ocean floor is positioned and later recovered using a hightensile wire and a winch located on a relatively large dynamicallypositioning vessel. However, this method is limited to certain depthsdepending on the recovery equipment's respective capability. As thedepth of water increases, so too does the challenges and cost ofpositioning and later recovering such equipment.

The preceding discussion of the background to the invention is intendedonly to facilitate an understanding of the present invention. It shouldbe appreciated that the discussion is not an acknowledgment or admissionthat any of the material referred to was part of the common generalknowledge as at the priority date of the application.

SUMMARY OF INVENTION

It is an object of this invention to provide a buoyancy system whichovercomes at least one of the problems of the prior art, or at leastprovides a useful alternative.

The present invention provides a buoyancy system for moving an object ina body of water, the system comprises:

at least one inflatable body which, when inflated, increases thebuoyancy of the object;

an inflation apparatus to inflate the at least one inflatable body;

an activation system to activate the inflation apparatus;

where upon activation of the activation system the inflation apparatuscauses a gas to flow to the at least one inflatable body, which onceinflated to the required volume enables the object to be moved.

Preferably the buoyancy system is adapted to move the object in asubstantially vertical orientation. The buoyancy system may be adaptedto cause the object to ascend or descend. When the buoyancy system isused in operations where the object descends, the system provides ameans to control the descent process.

The at least one inflatable body may be secured to the object.Preferably a shock absorbing device extends between the at least oneinflatable body and the object. The shock absorbing device will ensurethat the object ascent, particularly the initial and end stages, isrelatively smooth.

Upon inflation each inflatable body preferably inflates external of theobject.

The at least one inflatable body may have a release means so that the atleast one inflatable body may be detached from the object. The releasemeans may be operated if the buoyancy system is unintentionallyactivated.

The at least one inflatable body may comprise at least one upperpressure relief valve to release excess gas from the inflatable body.The requirement to release excess gas may be as a result of excess gasgenerated by the inflation apparatus, or may result from the expansionof the volume of gas in the inflatable body as the object ascends andthe pressure exerted on the inflatable body from the body of waterdecreases.

Once the object has reached the required depth the pressure relief valvemay lock closed to ensure the inflatable body remains inflated. Thiswill retain the object at the desired level.

The at least one inflatable body may also comprise at least one lowerpressure relief valve located at the bottom of the inflatable body. Theat least one lower pressure relief valve may vent any increases in thepressure within the inflatable body once the at least one upper pressurerelief valve is locked. This will prevent the at least one inflatablebody over inflating and possibly rupturing.

The pressure relief valve may have a valve piston which is biased to aclosed position. As the pressure against an external surface of thevalve piston increases, the valve piston moves to allow the excess gasto vent from the inflatable body. Upon the initial movement of the valvepiston, a locking means is released such that upon the valve pistonreturning to its closed position, the locking means locks the valve insaid position.

The at least one inflatable body may also comprise a one way valvebetween the inflation apparatus and an opening into the inflatable body.This will prevent the gas delivered into the inflatable body returningto the inflation apparatus.

In one aspect of the invention the at least one inflatable body issecured to a winch, whereby the winch feeds line out to the at least oneinflatable body. This would allow the object to descend whilst the atleast one inflatable body remains on the surface. When the object isrequired/able to ascend the winch is activated and the object movesupwardly. Similarly, the winch can be used to lower the object to agreater depth should the weather on the surface be poor, or to allow forcontrolled positioning of the object on the ocean floor.

Preferably the at least one inflatable body is made from a materialbeing heat resistant and having high tensile strength properties. Aninner layer of the at least one inflatable body may be made from amaterial which is heat resistant and has high tensile strengthproperties Preferably the inflatable body is in the form of aninflatable bag.

Preferably the buoyancy system comprises a plurality of inflatablebodies.

Preferably the plurality of inflatable bodies is positioned to ensurethe object is raised or lowered in a desired orientation.

Preferably the buoyancy system also comprises control means to maintainthe object at a certain level, such as at the surface of the water. Onceinflated the inflatable body may remain inflated for a predeterminedperiod of time.

Preferably the buoyancy system comprises an inflation apparatus for eachinflatable body.

The inflation apparatus may comprise a regulatory apparatus to regulatethe amount of gas passing in to the at least one inflatable body.

In one aspect of the invention the regulatory apparatus may behydrostatically governed whereby the regulatory apparatus will providethe required volume of gas in order to account for the external pressureand allow the inflatable body to inflate to provide the desired amountof buoyancy. As the pressure exerted upon the object increases thedeeper the object travels, the pressure required to inflate theinflatable body also increases.

The regulatory apparatus may comprise hydrostatic pressure sensors.

The inflation apparatus may comprise a gas generation system, a gasstorage system or it may be connected to an active gas generatingsystem, or a combination of these systems.

The gas generation system may comprises a gas generating medium such asfor example an explosive, propellant or other chemical compoundcontained within at least one vessel, whereby a charge activates themedium, creating a gas within the at least one vessel at pressure. Theat least one vessel may have a series of passages and/or baffles locatedtherein between the medium and a vessel outlet, whereby the gasgenerated by the medium passes through the passages before exiting theat least one vessel. This will ensure the vessel outlet is not exposedto the initial force of the medium as it generates gas.

The medium may be activated by an initiator or a detonator which isoperably connected to the activation system. The gas generation systemmay comprise more than one initiator or detonator in the event that oneor more of the initiators or detonators does not function correctly.

Preferably the molecular weight of the generated gas is closely matchedto that of air.

Preferably the vessel outlet is connected to a gas delivery regulator sothat the gas delivered to the inflatable body is delivered at thedesired pressure.

Preferably the gas generated from the medium is cooled prior to beingdelivered to the at least one inflatable bag.

The inflation apparatus may also comprise a reservoir. When the objectis descending, the reservoir may supply gas into the at least oneinflatable body to ensure it retains the desired inflation, controllingthe rate of descent and maintaining the weight, or negative buoyancy ofthe object. Preferably when the reservoir reaches a predeterminedpressure the gas supply or gas generators are activated to supplyfurther gas.

In this application, the buoyancy system might be attached to a loweringor guiding wire, whereby the buoyancy system removes the vast majorityof the weight or negative buoyancy to allow the object to be easily andaccurately positioned on the ocean floor. Previously, the capacity ofthe cable would limit the allowable weight of the object being placed onthe ocean floor at one time. In those applications in which the buoyancysystem is used, the weight of the object may be significantly more asthe buoyancy system would alleviate the weight burden which wouldotherwise be required to be restrained by the cable.

Once at the surface, the at least one inflatable body may be flushedthrough with a supplied gas to dilute and/or remove the gas that wasgenerated during the gas generation process. This function may beactivated automatically and comprise of hydrostatic sensors or beactivated manually or remotely. This will ensure any toxic gas has beendischarged from the inflatable body prior to a recovery unit collectingthe object.

The gas storage system may comprise a gas storage cylinder containingthe gas. Preferably the gas storage cylinder is in fluid communicationwith the at least one inflatable body through an outlet passage. Theoutlet passage may have one or more pressure retaining disks to preventthe gas leaving the gas storage cylinder. Each pressure disk may beconnected to a detonator. Each detonator may be operably connected tothe activation system.

The active gas generating system may incorporate a gas supply externalof the buoyancy system. Where the object is a submarine, this gas supplymay be the compressed air produced for submarine operation. Theactivation system may comprise a cross valve which fluidly connects thebuoyancy system with the gas supply.

The inflation apparatus may comprise at least one hydrostatic sensor orpressure relief valve which is adapted to discontinue the delivery ofgas to the at least one inflatable body once ascent has commenced. Oncethe ascent has commenced the inflatable body will continue to inflateeven if there was no more gas being provided to the inflatable body asthe gas inside the inflatable body expands as the external pressurereduces.

The activation system may be activated in a variety of ways, largelydictated by the particular application. The buoyancy system mayincorporate a plurality of activation systems. This is particularlyimportant in applications relating to submarines and aircraft as it willensure the buoyancy system can be activated regardless of the situation.

The activation system may be adapted to activate automatically when theobject is at a predetermined depth. Such an application may occur when asubmarine is damaged and is unable to return to the surface, or when anaircraft lands in water.

The activation system may be hydrostatically activated when the objectreaches a predetermined depth. The automatic activation system maycomprise one or more hydrostatically operated devices fitted external ofthe object. In the case of a submarine these devices may be locatedexternal to the pressure hull.

The hydrostatically operated device may comprise a substantially sealedunit having an exposed face with a series of perforations therein. Theexposed face may be adjacent a first plate. The first plate may bebiased into a normal condition whereby it is in spaced relation to asecond plate. As the hydrostatic pressure increases, the pressure actingthrough the series of perforations causes the first plate to movetowards the second plate. As the hydrostatic pressure increases furtherthe first plate engages the second plate, completing a circuit toactivate the activation system.

The activation system may comprise an override mechanism so that theautomatic operation of the activation system can be disabled should itbe required that the object descend below the predetermined depth.

The activation system may be acoustically operated.

In those arrangements in which the buoyancy system is fitted to asubmarine, the activation system may be incorporated into thesubmarine's emergency blow/surface system.

The activation system may be manually operated.

Also in those instances where the object is a submarine or similarvessel in which an operator may be contained, the activation system maybe internally activated from within the object.

The internal manual activation system may comprise a control panelwithin the submarine. The control panel may comprise a prime button toprime the activation system and an initiate button to activate theactivation system. The control panel may also comprise a continuitybutton to check the integrity of the activation system and to commencethe sequence of activating the activation system from the control panel.This is to ensure the buoyancy system is not accidentally activated.

The control panel may also comprise the release means to release the atleast one inflatable body.

The manual activation system may also be externally activated by aremote operating vehicle (ROV). The external manual activation systemmay comprise a docking mount external of the object to which the ROV maydock. The ROV may be adapted to move the docking mount from a normalcondition to an engaged condition wherein the activation system isactivated. The external manual activation system may be adapted suchthat a unique key is required to access the system.

Preferably once the external manual activation system is activated theat least one inflatable body has a delayed inflation sequence to provideample time for the ROV to disengage and move away from the object.

The buoyancy system may be powered from a generated power supply or froma battery pack.

The object may have a plurality of buoyancy systems. The activationsystem of each of the plurality of buoyancy systems may be synchronisedto activate simultaneously or within a prescribed time of each other.

Preferably the buoyancy system incorporates a locating beacon, such asan EPIRB, which is activated when the buoyancy system is activated. Thelocating beacon may be connected to the at least one inflatable body.

The buoyancy system may also comprise a propulsion means, whereby thepropulsion means may be used to move, direct or guide the object in avariety of directions. Gas may be used to operate the propulsion means.The gas may be provided by the gas generation process.

In one application of the invention the object is a submarine.Preferably the buoyancy system does not substantially affect theacoustic characteristics or fluid dynamics of the submarine. Thebuoyancy system may be substantially contained within the submarine'scasing until it is activated. The buoyancy system may be substantiallycontained between the submarines casing and pressure hull. The buoyancysystem may be sealed in a recess extending from the casing to thepressure hull. The recess may have a cover there across. The cover maybe released from the recess when the activation system is activated.

In another application of the invention the object is an aircraft, suchas a helicopter or aeroplane. In these applications there may be aplurality of buoyancy systems. Each buoyancy system may be strategicallyplaced to ensure the aircraft is raised or remains in a desiredposition.

In another application of the invention the object is a diving suit orROV. In the case of the ROV, the ROV may comprise means to disengagefrom its connection to a surface vessel.

In another application of the invention the object is a decompressionchamber.

In a further application of the invention the object is productioninfrastructure or drilling equipment, including sub-sea trees,manifolds, and booster pumps. In such an application the buoyancy systemmay also comprise at least one guide wire extending from the watersurface to the ocean floor. The guide wire provides a steadying line tocontrol the object's ascent and predict its surfacing position.

The buoyancy system may also comprise at least one lifting strop securedto the object. This will allow the object to be recovered upon reachingthe surface. The strop may be positively buoyant. This will ensure thestrop remains in a vertical orientation for recovery.

When raising a sub-sea manifold from the ocean floor, other subseainfrastructure, pipes, cables etc are disconnected and the buoyancysystem attached to the object's hard eye/lifting point prior toactivating the buoyancy system.

This invention provides the next generation in deepwater heavy sub-searecovery, salvage and installation. This new generation of deep waterrecovery consists of a concept of ‘floating’ the object to the surfaceregardless of the depth of water, to allow a surface vessel to recoverthe object inboard or tow it to a nearby port. It also allows for thecontrolled descent and installation of the object on the ocean floor.

The present invention further provides a buoyancy system for raising asubmerged object towards the surface of a body of water, the systemcomprises:

at least one inflatable body which, when inflated, increases thebuoyancy of the submerged object;

an inflation apparatus to inflate the at least one inflatable body;

an activation system to activate the inflation apparatus;

wherein upon activation of the activation system the inflation apparatusinflates the at least one inflatable body to inflate, which onceinflated to the required volume enables the submerged object to movetoward the surface of the body of water in which it is submerged.

The present invention further provides a buoyancy system for raising asubmarine to the surface of a body of water, the system comprises:

at least one inflatable body which, when inflated, increases thebuoyancy of the submerged object;

an inflation apparatus to inflate the at least one inflatable body;

an activation system to activate the inflation apparatus;

wherein upon activation of the activation system the inflation apparatuscauses the at least one inflatable body to inflate which once inflatedto the required volume enables the submarine to move toward the surfaceof the body of water in which it is submerged.

Preferably the buoyancy system comprises means to maintain the submarineat the surface a sufficient time to allow the Submariners to escape.

The present invention provides a buoyancy system for raising productioninfrastructure or drilling equipment from the ocean floor for recovery,the buoyancy system being adapted to be connected to the equipment, thesystem comprises:

at least one inflatable body which, when inflated, increases thebuoyancy of the equipment;

an inflation apparatus to inflate the at least one inflatable body;

an activation system to activate the inflation apparatus;

wherein upon activation of the activation system the inflation apparatuscauses the at least one inflatable body to inflate which once inflatedto the required volume enables the equipment to move toward the surfaceof the body of water in which it is submerged.

The buoyancy system may be incorporated in a cradle which is adapted tobe secured to the equipment. The cradle may be positively buoyant suchthat when it is attached to the equipment the buoyancy system remains ina desired orientation. The cradle may be connected to the equipmentprior to the equipment being returned to the surface.

In such an operation a strop may be connected to the equipment to assistthe recovery operation.

Also, the equipment may be connected to a guide wire extending betweenthe ocean floor and surface, whereupon ascent the guide wire guides theascent allowing the recovery location of the equipment to be predicted.

The equipment may remain below the surface until a vessel can attach acrane to the strop in order to lift the equipment from the ocean or totow the object to a port with cranage facilities.

The present invention provides a buoyancy system for lowering productioninfrastructure or drilling equipment to the ocean floor, the buoyancysystem being adapted to be connected to the equipment, the systemcomprises:

at least one inflatable body which, when inflated, increases thebuoyancy of the equipment;

an inflation apparatus to inflate the at least one inflatable body;

an activation system to activate the inflation apparatus;

wherein upon activation of the activation system the inflation apparatuscauses the at least one inflatable body to inflate, partly offsettingthe weight of the equipment and controlling the rate of descent towardsthe ocean floor.

Preferably the system comprises a reservoir which contains a gas, thereservoir supplying gas into the at least one inflatable body.

When moving the equipment to the ocean floor the equipment is liftedinto the water or towed floating on the surface to the deploymentposition whereby the at least one inflatable body is fully inflated and,if fitted, the reservoir pressurised. Upon descent the activation systemwill activate the inflation apparatus causing the at least oneinflatable body to remain inflated whereupon the object is more easilyand accurately moved toward the ocean floor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by reference to the followingdescription of several specific embodiments thereof as shown in theaccompanying drawings in which:

FIG. 1 is a view of a submarine at the bottom of the ocean floor havinga first embodiment of a buoyancy system according to the inventioninstalled thereon;

FIG. 2 is a view similar to FIG. 1 but with the buoyancy systemdeployed;

FIG. 3 is a schematic of the buoyancy system as installed on thesubmarine;

FIG. 4 is a schematic of a buoyancy system according to a secondembodiment;

FIG. 5 a, b is a schematic of an activation system of the buoyancysystem;

FIG. 6 a, b is a plan and side cross sectional view of a hydrostaticsensor of the buoyancy system;

FIG. 7 is a cross sectional schematic view of a gas generation system ofan inflatable apparatus of the buoyancy system;

FIG. 8 is a cross sectional schematic view of a gas storage system ofthe inflatable apparatus of the buoyancy system;

FIG. 9 a, b is a plan view and side view of an inflatable bag of thebuoyancy system in an inflated condition;

FIG. 10 is a cross sectional view of a pressure relief valve;

FIG. 11 is a schematic view of an inflatable bag and associated vesselsaccording to the second embodiment shown in FIG. 4;

FIG. 12 is a schematic view of a buoyancy system according to a thirdembodiment of the invention;

FIG. 13 is a schematic view of a buoyancy system according to a fourthembodiment of the invention;

FIG. 14 is a schematic view of a buoyancy system according to a fifthembodiment of the invention as fitted to a helicopter;

FIG. 15 is a schematic view of a buoyancy system according to a sixthembodiment of the invention as fitted to an aeroplane; and

FIG. 16 is a schematic view of a buoyancy system according to a seventhembodiment of the invention as fitted to a refuge chamber.

FIG. 17 is a schematic plan view of a buoyancy system according to aneighth embodiment of the invention for recovery of equipment from theocean floor;

FIG. 18 is a view similar to FIG. 17 but with an upper level removed;

FIG. 19 is a side view of FIG. 17;

FIG. 20 is a schematic view of the buoyancy system of FIGS. 17 to 19shown in two stages of recovery of equipment from the ocean floor;

FIG. 21 is a schematic side view of a buoyancy system according to aninth embodiment of the invention, the buoyancy system is connected toan object and is adapted to lower the object to the ocean floor;

FIG. 22 is a schematic plan view of FIG. 21 without the inflatablebodies shown;

FIG. 23 a, b are schematic views of alternate ways the buoyancy systemof FIG. 21 may be deployed on the ocean floor.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

The present invention has many applications across numerous industries.Certainly many more applications are also possible and these will cometo light in the future, particularly owing to the human quest to explorethe ocean depths.

Outlined below are several applications across several differentindustries. The majority of the below embodiments discuss applicationsin which a submerged object is raised towards the ocean's surface.However, the invention also has applications in controlled descent ofobjects to the ocean floor, maintaining an object at a required depthand in propelling objects through the ocean.

The invention according to the various embodiments is in the form of abuoyancy system 11 for either raising an object 12 towards the surface15 of a body of water, to lower the object 12 towards the ocean floor14, or for maintaining it at the surface 15 or at a desired depth.

The buoyancy system 11 comprises a combination of one or more inflatablebodies 16, one or more inflation apparatuses 19 and one or moreactivation systems 21. In different applications and circumstances thebuoyancy system 11 is configured to incorporate the required quantityand configuration of the aforementioned components.

Referring to FIGS. 1 and 3, the invention according to a firstembodiment is in the form of a buoyancy system 11 fitted to a submarine13. FIG. 1 shows the submarine 13 in a position on the ocean floor 14.This may occur when the submarine 13 malfunctions or has been damaged.The present invention would allow the submarine 13 shown in FIG. 1 to bereadily returned to the surface 15 by activation of the buoyancy system11.

FIG. 2 shows the submarine 13 after the buoyancy system 11 has beenactivated and the plurality of inflatable bodies 16, in the form ofinflatable bags 17, have been caused to deploy. As shown, the submarine13 is raised to the surface 15 in an upright position, allowingpersonnel to escape the submarine 13.

Submarines 13 are typically constructed to have a pressure hull 81 andan outer casing 83 towards the top of the vessel, wherein the two arespaced apart. This spacing provides an area in which the inflatable bags17 may be stored in modules 18. It also permits the buoyancy system 11to be fitted to a submarine without negatively affecting the fluiddynamics or acoustic characteristics of the submarine 13.

For submarines 13 without the outer casing 83, inflatable bags 17 may bestored in modules 18, engineered & incorporated into the pressure hull81.

The components of the buoyancy system 11 according to this embodimentare best shown in FIG. 3.

The buoyancy system 11 comprises an inflatable apparatus 19, which inthis embodiment, is provided by an active gas generating system 23whereby the gas to inflate the inflatable bags 17 is provided by a gassupply 25 external of the buoyancy system 11. The external gas supply 25is provided by the submarines internal air supply 27.

The inflatable apparatus 19 is activated by an activation system 21. Theactivation system 21 in this embodiment includes a manual externalactivation system 21 a, a manual internal activation system 21 b and anautomatic activation system 21 c. This provides multiple means toactivate the buoyancy system 12, ensuring the submarine 13 may be raisedto the surface regardless of the circumstances. Obviously otherapplications of the buoyancy system may only require one of theseactivation systems.

FIG. 5 best illustrates the components of the activation system 21utilised in this embodiment.

The manual external activation system 21 a may be operated by a remoteoperating vehicle (ROV), not shown. The ROV is adapted to engage adocking mount 29 through which the activation system 21 can beactivated.

The manual internal activation system 21 b may be operated from withinthe submarine 13 at one of three control panels 31.

The automatic activation system 21 c comprises a hydrostatic operateddevice 33 fitted external the pressure hull 81. In this embodiment thereare six hydrostatic operated devices 49 secured to the pressure hull 81.

Each hydrostatic operated device 49 comprises a substantially sealedunit having an exposed face 51 with a series of perforations 53 therein,as shown in FIG. 6 a. The exposed face 51 is adjacent a first plate 55as shown in FIG. 6 b. The first plate 55 is biased away from a secondplate 57 by a spring 59 such that in a normal condition the first plate55 and second plate 57 are in spaced apart relation.

As the submarine 13 reaches a predetermined depth, the pressure actingthrough the perforations 53 causes the first plate 55 to move toward thesecond plate 57 until a contact brush 61 a on the underside of the firstplate 55 engages a contact brush 61 b on the upper side of the secondplate 57. This completes a circuit resulting in activation of theinflatable apparatus 19, which leads to deployment of the inflatablebags 17.

Considering the external manual activation system 21 a as shown in FIG.5, the external manual activation system 21 a comprises the dockingmount 29 having a nut 69 adapted to be rotated by an ROV. The nut 69 isthreadingly received in a housing 71 of the docking mount 29. The nut 69is uniquely configured such that only an ROV with a correctly configuredarm is able to operate the nut 69. The nut 69 can be removed from thehousing 71 to allow the ROV to access an activation screw 73, which isalso threadingly received in the housing 71. Upon turning the activationscrew 73 it engages an activation plate 75. Upon engagement therewith acircuit is completed and the activation system 21 activates theinflation apparatus 19. In order to allow the ROV to disengage and moveaway from the submarine 13, there will be a delay before the inflatablebags 17 inflate and the submarine 13 moves upwardly.

Considering the internal manual activation system 21 b as shown in FIG.5, the control panel 31 comprises a prime button 77 to prime theactivation system and an initiate button 79 to activate the activationsystem. The control panel 31 also comprises a continuity button 85 tocheck the integrity of the activation system 21 and to commence thesequence of activating the activation system 21 b from the control panel31.

The control panel 31 also comprises the release means 87 to release theinflatable bags 17 upon accidental activation of the buoyancy system 11.

The control panel 31 also comprises an override switch 89 which can beused to override the automatic activation system 21 c as may be requiredshould the submarine be required to go below the predetermined depth.

The inflatable bag 17 in an inflated state is best shown in FIGS. 9 a,b. Each inflatable bag 17 comprises four upper pressure relief valves 91designed to release excess gas from the inflatable bag 17, as well asthe excess volume of gas generated as the submarine 13 ascends and thepressure exerted on the inflatable bag 17 from the body of waterdecreases. Once the submarine 13 has been raised to the required depththe pressure relief valve 91 locks, preventing any further gas frompassing therethrough to ensure the inflatable bag 17 remains inflated.

The inflatable bag 17 also comprises two lower pressure relief valves 93located in the lower region of the inflatable bag 17. The lower pressurerelief valves 93 vent any increase in the pressure within the inflatablebody once the upper pressure relief valves 91 lock.

Referring to FIG. 10, each pressure relief valve 91, has a valve piston95 biased to a closed position. As the pressure against an externalsurface 97 of the valve piston 95 increases from the pressure within theinflatable bag 17 the valve piston 95 moves to allow the excess gas tovent from the inflatable bag 17 via the relief valve 91. Upon theinitial movement of the valve piston 95, a locking means 99 is releasedwhereby, upon the valve piston 95 returning to its closed position, thevalve means 99 locks the valve piston 95 in said position.

Each inflatable bag 17 also comprises a one way valve 101 between theinflation apparatus 19 and an opening 103 of the inflatable bag 17. Thiswill prevent the gas delivered into the inflatable bag 17 from returningto the inflation apparatus 19.

Each inflatable bag 17 also incorporates an EPIRB 105 which is activatedwhen the bag 17 is inflated.

If the buoyancy system 11 is require to be operated, the activationsystem 21 will either be activated automatically, or manually fromexternal or internal of the submarine 13. Upon activation the inflationapparatus 19 is activated to divert gas from the gas supply 25 externalfrom the buoyancy system 11. The gas is used to inflate the bags 17until sufficient lift is created to raise the submarine 13 to thesurface 15.

A second embodiment of the invention is shown in FIG. 4. This embodimentis very similar to that of the first embodiment and so like componentswill be similarly numbered. This embodiment builds on the firstembodiment in that the inflation apparatus 19 of the buoyancy system 11now also comprises a gas generating system 35 and a regulatory apparatus43. In this embodiment the buoyancy system 11 does not rely solely onthe supply of gas from the submarine 13.

In this embodiment the gas generating system 35 comprises a set of sixvessels 37 for each inflatable bag 17, as shown in FIG. 11. Each vessel37 is connected to a hydrostatic operated device 49 and is associatedwith the regulatory apparatus 43 to regulate the amount of gas passingin to the inflatable bags 17, taken into account the depth of thesubmarine 13.

Referring to FIG. 7 each vessel contains a gas generating medium 39,such as an explosive, propellant or other chemical compound which, upondetonation and/or activation, creates a gas. This gas is channelledthrough the outlet 41 of the vessel 37 to fill the inflatable bag 17.The gas may be cooled before entering the inflatable bag 17.

The regulatory apparatus 43 is located upstream from the outlet 41. Inorder to shield the regulatory apparatus 43 from the force of the rapidgas generation a series of passages/baffles 45 are located between themedium 39 and outlet 41. These passages 45 cause the force of the rapidgas generation to pass along a longer path, dampening the full effect ofthe explosion and rapid increase in pressure.

The medium 39 is ignited by an initiator or detonator 47 connected tothe activation system 21. FIG. 7 shows the medium 39 as having threedetonators 47. This provides back up should one or two of the detonators47 malfunction.

As shown in FIG. 11 each inflatable bag 17 is secured to the submarine13 at a mounting point 63 which is secured to the pressure hull 81. Theinflatable bag 17 and vessels 37 are located in the module 18. Themodule 18 has a cover 65 which is released upon removal of pins 67.These pins 67 are removed by detonation when the activation system 21 isactivated.

The deployment of the inflatable bags 17 in this embodiment closelyfollow that as described for the first embodiment.

According to a third embodiment of the invention the inflation apparatus19 comprises a gas storage system 107. This embodiment is very similarto that of the second embodiment and so like components will besimilarly numbered. However, in this embodiment, rather than generategas via medium 39, the gas is stored in a high pressure gas cylinder109, as shown in FIG. 8.

In this embodiment the gas cylinder 109 of the gas storage system 107has an outlet 111 which is in fluid communication with the inflatablebag 17. The gas is retained in the cylinder 109 by three retaining disks113. Each disk 113 is connected to a detonator 115 which, when activatedthrough the activation system 21 causes the disks 113 to rupture toallow the gas to pass to the bag 17. A further detonator 115 a ispositioned such that its charge is directed to the face of the disks113. This will ensure the disks 113 are ruptured and the gas is able topass through.

FIG. 12 illustrates the configuration of the module 18 for storing theinflatable bags 17 according to this third embodiment.

A fourth embodiment of the invention is shown in FIG. 13. Thisembodiment has an inflatable apparatus 19 comprising a hybrid systemincorporating the gas generation system 35 and gas storage system 107.FIG. 13 represents how the inflatable apparatus 13 and inflatable bag 17of this embodiment would be configured in a module 18.

In a fifth embodiment of the invention, as shown in FIG. 14, fourindividual buoyancy systems 211 are strategically placed on a helicopter213. In this embodiment the inflatable apparatus 19 is in the form of agas generation system 35, whilst the activation means is in the form ofan automatic activation system 21 c and a manual internal activationsystem 21 b.

FIG. 15 shows a sixth embodiment of the invention. This embodiment issimilar to the fifth embodiment but instead of relating to a helicopterit is in relation to an aircraft 223.

In a seventh embodiment of the invention, as shown in FIG. 16, abuoyancy apparatus 311 is secured to a chamber, in this case asaturation diving bell 313. The buoyancy system 311 is similar to thatdescribed in the fifth and sixth embodiments but also incorporates awinch 315. This will allow the bell 313 to be lowered away from thesurface 15 if required.

As identified in the above embodiments, this invention provides a thirdgeneration escape and rescue system. The third generation of escape andrescue/abandonment technology consists of a concept of ‘self help’ thatis capable of achieving a successful outcome regardless of the depth ofwater in which the asset (e.g. submarine, diving bell) is operating orlocated. In the event of a malfunction or the asset is damaged (loss ofpower, fire, flood, collision, mechanical failure or indeed any incidentthat could disable the asset), the ability to surface immediatelynegates the requirement to conduct risky buoyant ascent escapes from theocean floor or wait for an operational rescue vehicle to be deployed. Itcould also prevent the asset from plunging to depths outside of itscapability (crush depth), avoiding complete loss of asset and allpersonnel.

Referring to FIGS. 17 to 20, the invention according to an eighthembodiment is shown. As this embodiment has components similar to thosementioned in the previous embodiments, like components will be similarlynumbered as those discussed above. In this embodiment the buoyancysystem 11 is used to raise or lower equipment, such as subsea manifolds401 from or to the ocean floor. FIG. 20 shows the buoyancy system 11raising a subsea manifold 401 from the ocean floor 14 (FIG. 20 b) to thesurface 15 of the ocean (FIG. 20 a) for recovery by a ship.

As shown in FIGS. 17, 18 and 19 the buoyancy system 11 in thisembodiment is supported on a cradle 403. The buoyancy system 11 has aninflatable bag 17 located on an upper level of the cradle 403 and isstored in a collapsed condition as shown in FIG. 17. Underneath theinflatable bag 17 is located the gas generation system 35 comprising 14vessels 37 which contain a medium 39, such as an explosive, propellantor medium for generating gas (not shown).

Each vessel 37 is coupled to a regulatory apparatus 43 and a hydrostaticsensor 407 for regulating the amount of gas which passes to theinflatable bag 17. Each vessel 37 is also coupled to a heat exchanger405 to assist in cooling the generated gas prior to passing into theinflatable bag 17.

The activation system 21 is in the form of an acoustically operatedactivation system 21 d and a manually operated activation system 21 awhich may be activated by an ROV. The activation system 21 is connectedto a power supply 409.

Referring to FIG. 20, two stages of the recovery process of the subseamanifold 401 is shown. The manifold 401 is secured to a guide wire 411which extends from the ocean floor to the surface 15. This assists inguiding the manifold 401 back to the surface 15 and provides a recoveryunit with an accurate location to recover the manifold 401 when it israised.

In the first stage of the process, the cradle 403 of the buoyancy system11 is secured to the manifold 401 and is positively buoyant so as toremain in an elevated position relative to the manifold 401. This may bedone by an ROV. At the same time a strop 413 is also connected. This isalso positively buoyant so that it remains above the manifold 401,allowing a crane from the recovery unit to easily lift the manifold 401from the ocean.

Once the buoyancy system 11 is secured to the manifold 401 and themanifold 401 has been disconnected from the surrounding infrastructure,the activation system 21 may be activated to cause gas to be generatedand fed into the inflatable bag 17. Upon activation, preferably throughmanual time delay or acoustic means, a charge is sent from the powersupply 409 to the hydrostatic sensors 407 that are responsible foractivating the gas generation vessels 37. Water pressure, throughhydrostatic sensors 407 determine the number of gas generation vessels37 activated to provide sufficient gas to inflate the inflatable body17. Gas produced by the gas generation vessels 37 pass through the heatexchanger 405 and regulator 43 providing gas to a pneumatic junctionwhich then delivers the inflation gas to the inflatable body 17 via apneumatic hose(s) 415.

Further inflation will result in the buoyancy system 11 moving themanifold 401 in an upward direction. The manifold 401 will then move toa recovery position whereby it sits below the surface 15 awaitingcollection by the recovery unit.

As the manifold 401 rises, the pressure acting on the inflatable bag 17reduces. In order to prevent the pressure of the gas inside theinflatable bag 17 from rupturing the inflatable bag 17, the excess gasis vented through the pressure relief valves 91 and/or 93 located at thetop and bottom of the inflatable bag 17 respectively.

As the inflatable bag 17 is fully inflated, excess gas is vented out ofthe inflatable bag 17 through pressure relief valves 91, 93. Uponreaching the surface, the gas pressure inside the inflatable bag 17reduces, the upper pressure relief valves re-seat and may lock in theclosed position to ensure that gas does not escape from the inflatablebag 17, ensuring that the manifold 401 remains near the surface 15.

The required size and inflation of the inflatable body 17 depends on theweight of the submerged object. The number and size of gas generationvessels required to be activated depends on both the size of theinflatable body and the depth at which the submerged object is resting.

Where the buoyancy system is attached to the manifolds 401 hardeye/lifting point, a positively buoyant lifting strop 413 is alsoattached. The positively buoyant lifting strop 413 is to be long enoughso it's hard eye/lifting point is on the surface and accessible once themanifold 401 arrives at the surface. This allows a surface vessel toconnect the positively buoyant lifting strop 413 to a suitable crane tolift the manifold 401 and the buoyancy system 11 out of the water andonto the deck of a ship, barge, etc.

Once recovered, the buoyancy system 11 can be detached from the manifold401, the inflatable body 17 deflated and repacked, activated/used gasgeneration vessels 37 replaced, upper relief valves 91 unlocked/resetand power supply 409 re-charged. The buoyancy system 11 then becomesready for re-deployment.

A similar system as shown in FIG. 20 may also be used to lower themanifold 401 to the ocean floor 14 in a controlled descent. In such anapplication the buoyant force provided by the buoyancy system 11 wouldneed to be slightly less than the force created by the weight of themanifold 401. However, as the manifold 401 descends further, it will benecessary to feed additional gas into the inflatable bag 17 to overcomethe additional pressure acting on the inflatable bag 17 so as tomaintain control of the descent. In this regard the buoyancy system 11may further comprise a reservoir (not shown) for retaining a gas whichmay bleed into the inflatable bag 17 as required.

Referring to FIGS. 17 to 20, the invention according to a ninthembodiment is shown. This embodiment has particular application in theexploration/mining industry. As this embodiment has components similarto those mentioned in the previous embodiments, like components will besimilarly numbered as those discussed above.

In this embodiment the buoyancy system 11 is particularly adapted tolower equipment 912 to the ocean floor. FIG. 21 shows the buoyancysystem 11 connected to an object 12, during descent to the ocean floor.The size of the object 12 will dictate the size of the buoyancy system,and/or the number of inflatable bodies 16 which are to be inflated forthe controlled descent.

The buoyancy system 11 has a securing point 903 to which is attached acable 909. The cable may be operated from a winch 914 located on a barge916 at sea level (FIG. 23 a), or by a crane on a ship 915 (FIG. 23 b).

In this embodiment the buoyancy system 11 comprises an inflatableapparatus 19 comprising a hybrid system incorporating a plurality of gasgeneration systems 35 and a gas storage system, in a similar manner asthat shown in FIG. 14.

The gas storage system comprises a pressure vessel 901. Prior to descentthe pressure vessel 901 is pressurised. In this embodiment thepressurisation is through high pressure gas line 912, which is connectedto pressure vessel 901 by quick release high pressure gas lineconnection 904.

Once pressurised. gas from the pressure vessel 901 passes through openregulators 905 to inflate inflatable bodies 16. Once the buoyancy system11 is fully immersed in water 15 and gas is venting from the pressurerelief valves 91 on all inflatable bodies 16 (signifying maximum upwardbuoyancy force) the buoyancy system 11 is ready for descent. The highpressure gas line 912 can then be disconnected from the pressure vessel901 and the buoyancy system 11 lowered to the sea floor by winch 914(FIG. 23 a) (or crane 913 (FIG. 23 b)).

The buoyancy system 11 is lowered at a rate that allows all inflatablebodies 16 to remain fully inflated. This can be monitored by a load cell(not shown) within winch 914 (or crane 913), or by observing the gasventing from the pressure relief valves 91 on the inflatable bodies 16.

Pressure inside the pressure vessel 901 is monitored by internalpressure sensors 906, which are in communication with the activationsystem 21. Once pressure within the pressure vessel 901 reduces to apre-determined pressure, as sensed by pressure sensors 906, theactivation system 21 sends an electronic charge to a gas generationsystem 35 a. The gas generation system 35 a then produces a gas whichfeeds into the pressure vessel 901, re-pressurising the pressure vessel901. This enables the pressure vessel 901 to provide a continuous supplyof gas to the inflatable bodies 16, thus ensuring full inflation.Obviously this is critical as the buoyancy system 11 descends deeper,exposing the inflatable bodies 16 to greater pressure.

If the pressure within the pressure vessel 901 reduces to thepre-determined pressure for a second time, as sensed by the pressuresensors 906, the activation system 21 will send an electronic charge toa further gas generation system 35 b to enable the pressure vessel 901to be re-pressurised. This process is repeated until the buoyancy system11 and the object 12 reach the sea floor.

Once the object 12 is placed in the required position on the sea floor,the inflatable bodies 16 can be deflated through dump valves 917. Thedump valves 917 may be activated by an ROV. Once all Inflatable bodies16 have been deflated, the securing points 907 securing the object 12 tothe buoyancy system 11 are released. The buoyancy system 11 is thenwinched back to the surface of the water 15 by winch 914 (or crane 913).

In an alternative embodiment, the buoyancy system 11 may cause one ormore of the inflatable bodies 16 to re-inflate once the object 12 isdisconnected from the buoyancy system 11. In this arrangement theinflated bodies 16 assist in returning the buoyancy system 11 to thesurface. This may be particularly relevant as exploration and miningoccur at increased depths. As depths increase the cable 909 needs to belonger and is therefore considerably heavier. It is thereforeadvantageous that the buoyancy system 11 can also assist in returningthe cable 909 to the surface once the object has been positioned on thesea floor.

The buoyancy system 11 shown in FIG. 21 is fitted with sufficient gasgeneration systems 35 to ensure the buoyancy system 11 provides therequired maximum upward buoyancy force until the object 12 is positionedon the sea floor. The required maximum upward buoyancy force will alsodetermine the number and size of Inflatable bodies 16.

Modifications and variations such as would be apparent to the skilledaddressee are considered to fall within the scope of the presentinvention.

Throughout the specification, unless the context requires otherwise, theword “comprise” or variations such as “comprises” or “comprising”, willbe understood to imply the inclusion of a stated integer or group ofintegers but not the exclusion of any other integer or group ofintegers.

1. A buoyancy system for moving an object in a body of water, the systemcomprises: at least one inflatable body which, when inflated, increasesthe buoyancy of the object; at least one inflation apparatus to inflateeach of the at least one inflatable body, the inflation apparatuscomprises a gas generation system; an activation system to activate eachof the at least one inflation apparatus; where upon activation of theactivation system the inflation apparatus causes a gas to be generatedfrom the gas generation system and flow to the at least one inflatablebody, which once inflated to the required volume enables the object tobe moved.
 2. The buoyancy system according to claim 1 wherein the atleast one inflatable body is secured to the object.
 3. The buoyancysystem according to claim 1 wherein the at least one inflatable bodyinflates external of the object.
 4. The buoyancy system according toclaim 1 wherein the at least one inflatable body has a release means sothat the at least one inflatable body may be detached from the object.5. The buoyancy system according to claim 1 wherein the at least oneinflatable body comprises at least one upper pressure relief valve torelease excess gas from the inflatable body.
 6. The buoyancy systemaccording to claim 5 wherein the pressure relief valve is locked in aclosed condition when the object has reached the required depth.
 7. Thebuoyancy system according to claim 1 wherein the at least one inflatablebody also comprises at least one lower pressure relief valve located atthe bottom of the inflatable body, wherein the at least one lowerpressure relief valve may vent any increases in the pressure within theinflatable body.
 8. The buoyancy system according to claim 5 wherein thepressure relief valve has a valve piston which is biased to a closedposition, whereby pressure acting on the valve piston causes the valvepiston to move to allow the excess gas to vent from the inflatable body,a locking means incorporated in the pressure relief valve is releasedupon movement of the valve piston, such that upon the valve pistonreturning to its closed position, the locking means locks the valve insaid position.
 9. The buoyancy system according to claim 1 wherein theat least one inflatable body also comprises a one way valve between theinflation apparatus and an opening into the inflatable body.
 10. Thebuoyancy system according to claim 1 wherein the at least one inflatablebody is at least partially made from a material being heat resistant andhaving high tensile strength properties.
 11. The buoyancy systemaccording to claim 1 wherein the inflation apparatus comprises aregulatory apparatus to regulate the amount of gas passing in to the atleast one inflatable body.
 12. The buoyancy system according to claim 11wherein the regulatory apparatus is hydrostatically governed whereby theregulatory apparatus will provide the required volume of gas in order toaccount for the external pressure and allow the inflatable body toinflate to provide the desired amount of buoyancy.
 13. The buoyancysystem according to claim 1 wherein the inflation apparatus alsocomprises a gas storage system and/or is connected to an active gasgenerating system for supplying a gas.
 14. The buoyancy system accordingto claim 13 wherein the gas generation system comprises a gas generatingmedium contained within at least one vessel, wherein the medium is anexplosive, propellant or other chemical compound which undergoes achemical reaction, producing a gas.
 15. The buoyancy system according toclaim 14 wherein a charge activates the medium to create a gas withinthe at least one vessel at pressure, the medium is activated by at leastone initiator or at least one detonator which is operably connected tothe activation system.
 16. The buoyancy system according to claim 14wherein the gas generated from the medium is cooled prior to beingdelivered to the at least one inflatable bag.
 17. The buoyancy systemaccording to claim 13 wherein the gas storage system comprises a gasstorage cylinder containing the gas, the gas storage cylinder being influid communication with the at least one inflatable body through anoutlet passage, the outlet passage has one or more pressure retainingdisks to prevent the gas leaving the gas storage cylinder, wherein eachof the one or more pressure discs may be ruptured to allow the gas toflow to the inflatable body.
 18. The buoyancy system according to claim1 wherein the inflation apparatus comprises a reservoir for supplyinggas into the at least one inflatable body to ensure it retains thedesired inflation during descent.
 19. The buoyancy system according toclaim 18 whereupon the reservoir reaching a predetermined pressure thegas supply or gas generators are activated to supply further gas tomaintain the pressure in the reservoir at a pressure equal or greaterthan the predetermined pressure.
 20. The buoyancy system according toclaim 1 wherein the activation system activates automatically when theobject is at a predetermined depth.
 21. The buoyancy system according toclaim 20 wherein the activation system is hydrostatically activated whenthe object reaches a predetermined depth, the automatic activationsystem comprising one or more hydrostatically operated devices fittedexternal of the object.
 22. The buoyancy system according to claim 1wherein the activation system is manually operated from within and/orexternal the object.
 23. The buoyancy system according to claim 22wherein the activation system is activated by a remote operating vehicle(ROV), the external manual activation system comprising a docking mountexternal of the object to which the ROV dock.
 24. A buoyancy system forraising a submerged object, such as a submarine, mining infrastructure,towards the surface of a body of water, the system comprises: at leastone inflatable body which, when inflated, increases the buoyancy of thesubmerged object; at least one inflation apparatus to inflate the atleast one inflatable body, the inflation apparatus comprises a gasgeneration system; an activation system to activate the inflationapparatus; wherein upon activation of the activation system the gasgeneration system produces a gas to inflate the at least one inflatable,which once inflated to the required volume enables the submerged objectto move toward the surface of the body of water in which it issubmerged.
 25. The buoyancy system according to claim 24 wherein theobjected is connected to a guide wire extending between the ocean floorand surface, whereupon ascent the guide wire guides the ascent allowingthe recovery location of the equipment to be predicted.
 26. A buoyancysystem for lowering production infrastructure or drilling equipment tothe ocean floor, the buoyancy system being adapted to be connected tothe equipment, the system comprises: at least one inflatable body which,when inflated, increases the buoyancy of the equipment; at least oneinflation apparatus to inflate the at least one inflatable body, theinflation apparatus comprises a gas generation system which produces agas for inflation; an activation system to activate the inflationapparatus; wherein upon activation of the activation system theinflation apparatus causes the at least one inflatable body to inflate,partly offsetting the weight of the equipment and controlling the rateof descent towards the ocean floor.
 27. The buoyancy system according toclaim 26 wherein the system comprises a reservoir which contains a gas,the reservoir supplying gas into the at least one inflatable body.